An Objective is a description of a goal to be achieved in the future. An Objective sets a clear direction and provides motivation. In OKR methodology objectives should be hard to reach, but not impossible, goals.
A Key Result is a metric with a starting value and a target value that measures progress towards an Objective. While and Objective is like a destination on a map, a Key Result is like a signpost with a distance that shows you how close you are.
OKR delivery cycle is a time period used to add time constraint to your objectives. Cycles can be freely defined by your company. Typically a cycle lasts one quarter.
Example: 2018 1st Quarter
Objectives can be vertically or horizontally aligned. Alignment indicates support for another objective, usually owned by another team at your company. For example, a company objective to Grow business might be supported by Marketing team's objective Create more leads.
Teams can be set as objective owners. Objectives are generally large in scope and will have several people working on the objective in order to reach it. You can designate team responsibilities by assigning objectives to teams.
Example: Product Engineering Team
Lead is a person who oversees an objective. Lead is a point person for any OKR related questions. Lead can be part of the team that owns the objective or someone completely outside the team.